FIrst things first. I'm not trying to get you to change your policies. You have reasons for maintaining them, and that's your choice. All I'm trying to do is say that pit bulls - and most other breeds that, at one time or another have had an "aggressive" reputation (i.e. german shepherds, doberman pinschers, rottweilers, etc.) - are not INHERENTLY aggressive.
As for the laws that were changed, most cities or counties have laws regarding what kinds of dogs can live in that area and under what circumstances. Where I live, the law used to be that any dog that "was or appeared to be" a pit bull or pit bull mix (I believe there were a couple other breeds specified as well, but at the time I was looking at it, I was mostly concerned about pit bulls.) Since that time - probably a decade or more ago - the law has been rewritten and doesn't exclude any specific breeds. Instead is based on the dogs behavior. When I was reading about dog laws, I found that many places that used to have breed-specific legislation no longer do because they found it was ineffective at fixing the problem of aggressive dogs, so they started focusing on the dogs themselves and not the breed.
This is from and ASPCA statement about Pit Bulls. The whole thing is quite good as it actually explains some of the genetics and such, but these are the most relevant portions to this conversation. The first part is on pit bulls themselves, and the second is about breed-restrictive laws:
The whole statement can be found at: https://www.aspca.org/about-us/aspca-po ... -pit-bullsToday’s pit bull is a descendant of the original English bull-baiting dog—a dog that was bred to bite and hold bulls, bears and other large animals around the face and head. When baiting large animals was outlawed in the 1800s, people turned instead to fighting their dogs against each other. These larger, slower bull-baiting dogs were crossed with smaller, quicker terriers to produce a more agile and athletic dog for fighting other dogs.
Some pit bulls were selected and bred for their fighting ability. That means that they may be more likely than other breeds to fight with dogs. It doesn’t mean that they can’t be around other dogs or that they’re unpredictably aggressive. Other pit bulls were specifically bred for work and companionship. These dogs have long been popular family pets, noted for their gentleness, affection and loyalty. And even those pit bulls bred to fight other animals were not prone to aggressiveness toward people. Dogs used for fighting needed to be routinely handled by people; therefore aggression toward people was not tolerated. Any dog that behaved aggressively toward a person was culled, or killed, to avoid passing on such an undesirable trait. Research on pet dogs confirms that dog aggressive dogs are no more likely to direct aggression toward people than dogs that aren’t aggressive to other dogs.
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Laws that ban particular breeds of dogs do not achieve these aims and instead create the illusion, but not the reality, of enhanced public safety. Notably, there are no statewide laws that discriminate based on dog breed, and 18 states have taken the proactive step of expressly banning laws that single out particular breeds for disparate legal treatment. Even the White House has weighed in against laws that target specific breeds. In a a statement issued in 2013, President Obama said “[w]e don’t support breed-specific legislation—research shows that bans on certain types of dogs are largely ineffective and often a waste of public resources. And the simple fact is that dogs of any breed can become dangerous when they’re intentionally or unintentionally raised to be aggressive.”
